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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

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300                              AIASKAN GLACIER STUDIES
All of these cascading ice streams were formerly tributaries to Harvard Glacier, and they have been detached from the main glacier as a result of its retreat northward past each successive cascade. In the same "way a further-retreat of Harvard Glacier for a mile and a half would transform Radcliffe Glacier into a separate cascading tongue.
Named in order from Harvard Glacier southward, these cascading ice falls are Baltimore, Smith, Bryn Mawr, Vassar, Wellesley, Barnard, and Holyoke Glaciers. On the eastern side of the fiord, opposite Baltimore Glacier, is Downer Glacier, which has rather recently ceased to be a tributary of Harvard. Smith, Bryn Mawr, Vassar, and Wellesley Glaciers have sufficient snow supply so that they still extend down the fiord wall and end in the water (PL C, B). The other cascading glaciers, with smaller snow-fields, end some distance above the fiord,1Q04 feet in the case of Baltimore Glacier and 950 feet in the case of Downer.
The slopes of these cascading glaciers average about 2500 feet to the mile, being very much greater in some parts than in others because the lower slope of the fiord has been much oversteepened by glacial erosion and because the upper parts of some of the glaciers are in hanging valleys. In each case the lower, or cascading portion of these glaciers is in a shallow valley, interrupting the slope of the fiord wall.
Several of the cascading glaciers have built terminal moraines and outwash fans in the fiord, giving rise to a narrow piedmont flat at the base of the western fiord wall. Vassar and Bryn Mawr Glaciers spread out upon this flat, so that below the ice cascade there is a gently-sloping terminus extending from the base of the mountain to the sea. Wellesley Glacier formerly had such an expanded foot, but has retreated so that a good-sized cove interrupts the narrow coastal plain, the glacier ending three quarters of a mile back from the main fiord. Within the cove the water is 48 feet deep.
From Downer, Baltimore, Barnard, and Holyoke Glaciers, which end high above the fiord, large streams descend in foaming waterfalls, building deltas where they enter the fiord. A similar stream descends the fiord wall from a minor lobe of Vassar Glacier, which ends 2000 feet above the fiord.
Downer and Baltimore Glaciers. This pair of ice tongues which would be the first ones to reunite with Harvard Glacier if there should be general advance, have not changed greatly since 1899, the period of photographic observations. Downer Glacier 1 is a clean, white ice tongue with no moraine. Beyond its end there is an extensive barren zone 950 feet above sea level, which shows that there has been retreat in recent years. Indeed, fully a third of this barren zone has developed since 1899, and part of it may be glacial ice, mantled with ablation moraine.
The stream from Downer Glacier descends through a steep-sided rock gorge, below which is the torrential delta, already referred to. Upon its surface, were shrubs, none over 6 or 7 years old, indicating that there had been no great activity of delta building since 1902 or thereabouts.
Baltimore Glacier, which is fed from snowfields that coalesce with those supplying Smith Glacier, is also a clean white ice mass, with no moraine except small medials near the terminus. Half a mile from the end it bifurcates, the north lobe being larger and and ending lower (1004 feet) than the south lobe. A barren zone about its terminus indicates that the glacier is less extensive than it was a few years ago; but while Rad-cliffe and other cascading glaciers to the south advanced between 1909 and 1910, there
1 Named in 1910 for the Milwaukee-Downer College for Women, in Wisconsin.